1. Field of the Invention
The present invention relates to a light energy conversion material.
2. Related Background Art
Studies on a light energy conversion material have so far been made. The light energy conversion material utilizes a photo-excited electron transfer reaction in which an electron is transferred from an electron donor to an electron acceptor in accordance with the absorption of light energy.
For example, Japanese Unexamined Patent Application Publication No. 2002-110260 (JP 2002-110260 A) discloses a light energy convers ion material including a photoactive pigment, an electron donor, an electron acceptor, and a porous material having a pore with a pore wall thickness of 2 nm or less. The photoactive pigment is disposed inside or outside the pore. At least one of the electron donor and the electron acceptor is disposed inside the pore. Additionally, the electron donor and the electron acceptor are not disposed directly adjacent to each other, but are separated by the pore wall.
However, in the conventional light energy conversion material as described in JP 2002-110260 A, it is necessary to introduce a large amount of the electron donor in the pore space to achieve the effect sufficiently. On the other hand, since the photoactive pigment and the electron acceptor were also disposed in the pore space, it is spatially difficult to introduce a sufficiently large amount of the electron donor in the pore. Consequently, the introduced amount of the electron donor is not always sufficient. Even if the pore space is filled with the sufficient amount of the photoactive substance and the electronic substance in the light energy conversion material, a chemical energy conversion reaction is not always sufficiently advanced using the pore space as a reaction field. Thus the energy conversion efficiency is not always sufficient.
On the other hand, with respect to a thin film in which luminescent molecules are introduced, a method of making a mesostructured inorganic silicate thin film in which a pair of luminescent molecules such as a ruthenium complex and pyrene are introduced in the spatially separated region is disclosed (refer to “Placement and Characterization of Pairs of Luminescent Molecules in Spatially Separated Regions of Nanostructured Thin Films” in J. AM. CHEM. SOC., 2002, 124, 14388-14396). With respect to a luminescent material, a silica porous material containing a specific organic group showing fluorescence or phosphorescence is disclosed in International Publication No. W02005/097944. However, it is not suggested to employ such a luminescent material and the like in the light energy conversion material.